Cache genesis call in web3-utils package

[mateuszsokola]

Currently this code:

    async def get_genesis(self) -> int:
        genesis = await self._run_as_async(super().get_genesis)
        genesis_time = int(genesis["data"]["genesis_time"])
        return genesis_time

Makes remote call each time the get_genesis is called. Let's add a local caching for the get_genesis response so that only first request to get_genesis calls rpc endpoint. This data does not change at all and we're wasting a lot of QuickNode quota.
Make sure to cache based on base_url.